Rights might be regarded as an objectionable and even a dangerous feature of moral, political, and legal arrangements. It is an element of all types of rights that Able's having right X entails requirements or prohibitions for Baker. These restrictions hold against Baker at Able's discretion, that is unless Able excuses Baker from respecting them. Nor are the restrictions merely decorative. We must presume that they are established because of the expectation that Baker would otherwise be disposed to interfere with the action Ms. Able's right warrants her in taking. Thus as writers as early as Spinoza have stressed, rights are powers – one might even say weapons – that Able may use against Baker. Of course, as a practical matter these “weapons” are frequently ineffective. Ms. Baker may willfully ignore her obligations and prevent Ms. Able from enjoying her entitlements. But such occurrences, as common and as unfortunate as they are, do not materially ease the task of justifying rights. It is only insofar as rights are effective, and hence only insofar as anyone will have reason to defend them, that they are weapons in Able's hands